Relief valve for hot water tanks and heating systems



RELIEF VALVE FOR HOT WATER TANKS AND HEATING SYSTEMS I Filed Feb. 24, 1939 connes FIG. 4

FIG.

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FIG. 6

Patented July 2, 1940 `RELIEF VALVE FDE HOT WATER TANKS AND'` HEATING SYSTEMS Edward F. Donnelly, Malden, and Thomas J. McCarthy, Peabody, Mass.

`.supplieation February 24, 1939, Serial No. 258,270

. 2 Claims.

` j, injured by extra strains and sometimes destroyed by explosions because of excessive water temperature or water pressure. `The injurious results and the danger involved are too well known to need further discussion herein. Unless the tanks or systems are provided with eiiicient means of relief from high temperature and pressure changes, the possibility of suoli results as have been mentioned is always present. p

An object of our invention is to provide means whereby water is released from the tank or system through a valve positioned within the tank upon rise of water temperature or water pressure above a safe limit.

, Another object is to provide means for permitting the water in the tank to .become more eioiently heated throughout before the safe limit of heating is reached. In this respect, we desire to call attention to the fact that other valves used for the purpose are so` positioned on the 15 tanks that they do not permit proper heating of all of the tank water because the excessive heat at the positions of the valves causes them to open before this desirable action is gained, thus causing delay, loss of water and increasing the 3U cost of heating the water.

Other advantages will be obvious to those skilled in the art and to users of the invention.

In the drawing that accompanies this application for a patent as a part thereof, Figure l shows our complete unit ready for installation; Figure 2 is a similar view, partly in section; Figures t and 4 are details showing adjustment guide; Figure 5 shows the unit applied through the top of a vertical tank; Figure 6 illustrates its application to old installations; Figure 7 shows it installed in a hot water heater of a heating system; and in Figure 8 it is set in through the side of a vertical tank.

Referring to the drawing, It is a relief casing having a relief chamber Illa therein, thechamber being closed at one end and at its open end having threads which engage a nipple ll to which a relief tube I2 is attached.v In the. side wall of the casing is aport IIlby in which is a ,fusible plug Ille. Also in the side wall of the casing is a port I Ild to which a tube I3 is attached. Attached vto the reliefI casing at its closed end is a thermostatic bellows I4, preferably by threaded engagementsothatthe bellows may be removed if desired; vA valve casing I5 with a valve chamber l5a has a port I5b in its side wall and is attached to tube I3 so that there is a continuous passageway for water between the valve chamber and relief chamber. An end wall of the valveA chamber comprises a valve seat I5c and a valve port I5d extends therefrom towards the free end of the bellows. The valve` casing has externally threaded extensions I5e and I5f. at the ends. A valve plunger IS in the valve chamber carries ay valve I 6a which engages the valve seat. The plunger extends through the valve port to the end of the bellows and also extends beyond the other end of the casing. The extensionV I 5f is threaded internally to engage an enlarged threaded head IlEt of ahollow guide Il in which the valve plunger is movably mounted. Positioned so as to surround the valve plunger and guide and butting against valve I6a and guide head Ila is a spring I8. The guide is shorter than theV distance between the guide head and valve in order to allow movement of the guide to adjust the tension of the spring. A screw cut I'lby in the outer end of the guide head permits adjustment of the spring by turning the guide to create greater or less tension of the spring as may be required for adjustment of the Valve to predetermined pressure demands as will be pointed out hereinafter. A cap 20 engages the exterior threads onextension I5f to prevent water from entering the valve chamber. The relief tube I 2' passes through a suitable detachable spud connection Isa in the tank I9. The external threads I5l on extension I5e of the valve casing are for the purpose of attaching the valve casing to water pressure testing apparatus.

The valve plunger and valve are made of a single piece of non-ferrous metal and there is substantially no expansion or contraction of the metal due to changes of temperature. Also, in the construction of the unit there are no washers o or gaskets. It is well known in the art that expansion and contraction of such parts often offset the predetermined adjustment of the thermostatic element andtension and are detrimental to the efficiency of the unit. In our construction no such conditions exist and the valve action is at all times positive at the-predetermined4 pressure and temperature adjustments. I In vertical tanks the unit is preferably positioned a little below the middle horizontal line` of the tank and in horizontal'tanks close to or resting on `the bottom side of the tank. The. device may be positioned otherwise, however, as through an end or side of either a vertical or horizontal tank. Also the valve may be' posi- Ationed elsewhere in the tank than in our preshown in Figure 5 the valve maybe positioned close to the top of the tank and with a longer tube it may be positioned at the bottom, all of which positioning comes within the scope of our invention.

In Figure 6 we have shown how our invention is positioned in old installations. We provide a T-itting 2| having a port to which the hot water distributing pipe 2W is connected. The relief tube l2 passes through a port in the T-tting and is held in position by the spud Isa. The diameter of the outlet from the tank is greater than the diameter o-f the relief tube so that when hot water is drawn it passes freely from the tank.l

In Figure '7 we have shown Ahow the relief valve is installed in a hot water heater for adjustment of temperature. 22 is a heater, 22a the hot water feed pipe, 22b the return pipe, 22 the cold water intake and 22d th'e water dome. Such installation and its operation will be understood without further description. y

The device is installed by removing the connection Vlila# from the tank, passing the relief tube through it and securing the tube in the connection so as to allow proper positioning of the relief valve in the tank, then passing the relief Valve through the connection port ofthe tank and positioning and tightening the connection |911.

Normally, the valve is closed and held in position by the spring. The ,endof the valve 'plunger is preferably in contact with the end of the bellows and there is no movement of water in the valve chamber, tube I3 and relief chamber. Rise of temperaturelabove a predetermined degree to which the device has been adjusted causes extension of the bellows to exert pressure on the valve plunger and overcome the resistance of the spring, thus causing the valve to open and allow water to flow from the tank through the valve port, valve chamber, tube I3 and relief chamber to and lthrough relief tube l2 to a drain pipe, sink or other receptacle.

Water pressure abo-ve the predetermined resistance pressure to which the spring has been adjusted forces the valve to open by direct'pressure of thewater on the valve through the valve port and allow water to flow through the valve chamber, tube i3, relief chamber and relief tube to 'tank requires a valve set to open at 85 pounds pressure; a 250 pound tank, at 106 pounds.; a 300 pound tank, at 127.5 pounds; and for 350 pounds or more, at 147.5 pounds. Our valve is adjustable for any of such pressures by changing the tension of vthe spring until the proper spring tension is applied to the valve.

As already stated, the valve operates to open upon vrise of temperature above a vpredetermined safe limit. This is made possible by charging the bellows with a proper amount of expansible huid to open the valve at such predetermined degree of temperature.

If for any reason the relief valve fails to operate upon rise of temperature, the fusible plug lilc is melted and water flows through the relief tube, as required by safety regulations.

It will beseen from the foregoing description that our invention is simple inl construction, economical to make and easily installed. In addition we desire to point out a distinct advantage over other constructions and installations. As has been stated, other safety valves are placed in the pipe line outside of the tank. The known result of such positioning of the valves is that the hottest water passes directly from the tank into the 'relief valv'e. while the water is being heated. As it is the practice to pass the hot water from the 'heater into the tank at or near the top, this water becomes highly heated before the rest of the tank water has become heated to the desired ytemperature for use. Under such conditions the thermostatic element of the relief valve causes the valve 'to operate frequently to run olf the hottest water and when this occurs cold water enters the tank and cools the water, thus preventing proper heating of the water throughout the tank. On the other hand, our preferred positioning of the valve permits complete heating of the tank water to a proper temperature without danger of the tank being injured, be-

' cause, as it is positioned well down in the tank,

the whole body of water becomes thoroughly heated to a safe degree of temperature before the water surrounding the unit becomes heated to the predetermined safe valve opening expansion of the bellows. Y

We have described our preferred construction but do not wish to be limited to the details thereof as modifications and alterations can be made that come' within the scope of our claims.v What we claim is:

a connected tube attached to the casings and communicating with the chambers therein through said ports in the casings, a valve seat in the valve casing, a valve port in the seat, a valve plunger passing through the valve chamber and port, a valve on the plunger adapted to make contact with the valve seat and normally seated thereon, an adjustable guide with an enlarged head movably mounted in the valve casing, eX- tending into the valve chamber and about the valve plunger, a spring mounted on the valve plunger and guide and positioned between the valve and guide head, the bellows being adapted to extend at a predetermined degree of heat and exert pressure on the valve plunger to open the valve and the valve being adapted to open upon rise of water pressure in the tank above a safe limit, to permit water to flow Athrough the valve port, valve chamber, the tube connection, relief chamber and relief tube to drainage, as described.

2. In a device of the described adapted to `be positioned in a hot water container, a relief chamber in a relief casing, a relief tube attached to the casing for providing communication between the relief chamber and drainage outside of the tank, a thermostatic bellows attached to the casing, a valve casing, a valve chamber in the casing, ports in the relief and valve casings, a

` connecting tube attached to the casings and communicating with the chambers therein through said ports in the casings, a valve seat in the valve casing, a valve port in the seat, a Valve plunger passing through the lValvechamloer and port, a valve on the plunger adapted to make Contact with the valve seat and normally seated thereon, an adjustable guide with an enlarged heat movably mounted in the Valve casing, extending into the valve chamber and guiding the valve plunger, a spring mounted about the valve plunger and guide and positioned between the valve and guide head, the bellows being adapted to extend at a predetermined degree of heat and exert pressure on the Valve plunger to open the Valve and the valve being adapted to open upon rise of Water pressure in the tank above a safe limit, to permit Water toliow through the valve port, valve chamber, the tube connection, relief chamber and. relief tube to drainage, the bellows being adapted to contract and release pressure on the Valve upon diminution of heat from said predetermined degree, the spring being adapted to exert pressure upon the Valve to close the valve port upon contraction oi the bellows and. also upon lowering of the Water pressure.

EDWARD F. DONNELLY.

THOMAS J. McC'ARTI-IY. 

